The present invention relates to a fitting construction of the thermostat, which is fit to an internal combustion engine and which controls the flow of a cooling fluid by blocking or communicating a cooling fluid channel.
At present, as commercially available cooling systems for engines, most of the systems are types which cool the engines by water-cooling. The water-cooled system prevents overheating due to the heating of the engine and prevents overcooling of the engine in cold times, always keeping the engine at an optimal temperature.
In the cooling system by water-cooling, a radiator is placed outside of an engine, and the radiator and the engine are connected by means of a rubber hose, etc. to circulate a cooling fluid. The main configuration of the water-cooled system is composed of the radiator, which plays a role as a heat exchanger, a water pump, which forcedly feeds the cooling fluid from the engine to the radiator, a thermostat, which controls the flow of the cooling fluid to or from the radiator depending upon a change in the temperature of the cooling fluid to keep the temperature of the cooling fluid at an optimal level, and a rubber hose, which forms a circulation channel for the cooling fluid, and the like. Such a water-cooled system for cooling an engine is utilized in an engine for a two-wheeled vehicle as well as an engine for four-wheeled vehicle.
The conventional fitting construction of the thermostat placed within the water-cooled internal combustion engine will now be described by referring to FIGS. 7 and 8. FIG. 7 is an explanatory view showing the condition where the conventional thermostat is fit to a general water-cooled internal combustion engine, and FIG. 8 is an elongated view of the portion where the thermostat is fit in FIG. 7.
As shown in FIG. 7, a thermostat 1xe2x80x2, in the state of being accommodated within a case or such, is placed in an appropriate portion of a cooling fluid channel 3xe2x80x2 formed between an engine E and a radiator R. As shown in FIG. 8, to the thermostat 1xe2x80x2 is fit a piston 16xe2x80x2 which moves forward and backward by means of an element 10xe2x80x2 so that the direction of the movement of the piston 16xe2x80x2 is parallel to the fluid channel of the cooling fluid (see the arrow in FIG. 8). By the movement of the piston 16xe2x80x2, a valve element 12xe2x80x2 and a valve seat 17xe2x80x2 are separated from or brought into contact with each other to block or communicate the cooling fluid channel. In FIG. 8, number 11xe2x80x2 is a guide portion which guides the movement of the piston 16xe2x80x2, number 15xe2x80x2 is a wax case in which a wax is stored, and number 20xe2x80x2 is a second valve element which blocks or communicates a bypass channel 3Axe2x80x2. In FIG. 7, symbol P is a water pump.
As shown in FIG. 7(a), the thermostat 1xe2x80x2 closes the cooling fluid channel 3xe2x80x2 during the course from starting the engine E up to increasing the temperature within the engine E to an optimal temperature. To be specific, since the cooling fluid from the engine E does not flow toward the radiator R and does pass through the bypass channel 3Axe2x80x2 to circulate within the engine E (see the arrow in FIG. 7(a)), the temperature of the cooling fluid will be soon increased to the optimal temperature. On the other hand, after the temperature reaches the optimal level, the valve element 12xe2x80x2 of the thermostat 1xe2x80x2 is opened to open the cooling fluid channel 3xe2x80x2 at the side of the radiator R. At this time, since the cooling fluid passes through the radiator R and circulates within the engine E (see the arrow in FIG. 7 (b)), the interior of the engine E is allowed to cool down to keep the temperature at the optimal level.
In the conventional thermostat 1xe2x80x2 to be placed in the internal combustion engine, the pipe diameter of the cooling fluid channel 3xe2x80x2 for placing the thermostat 1xe2x80x2 must be large in order to maintain the flow amount of the cooling fluid to the cooling fluid channel 3xe2x80x2. However, in the case of utilizing the cooling fluid channel 3xe2x80x2 having a large diameter, the requirement of making an effective layout cannot be attained.
Moreover, the design of the pipe diameter is restricted in many ways, and a channel having a large diameter is difficult to be manufactured; thus, the place for fitting the thermostat is restricted in many ways.
Even if an appropriate pipe diameter is designed and the channel is manufactured, it is very difficult to place the thermostat within the pipe at an appropriate position, and its workability may be very poor.
An object of the present invention is to solve the above problems and to provide a fitting construction of the thermostat which moderates the restrictions concerning the fitting of the thermostat, and which can improve the workability of the installation.
The present invention which can attain the above object is a fitting construction of the thermostat, said thermostat possessing
an inlet opening and an outlet opening formed on the circumference of the thermostat,
a cylindrical valve body fixed onto a position where said inlet opening and said outlet opening communicate a cooling fluid channel of an internal combustion engine,
a fluid channel area which communicates said inlet opening with said outlet opening within a cooling fluid channel of the internal combustion engine; and
a valve element which actuates forward and backward by the function of a piston portion and a spring portion depending upon a temperature change in the cooling fluid to cross said fluid channel, and which blocks or communicates said fluid channel by the forward or backward movement,
said construction possessing:
an insert hole which is formed across said cooling fluid channel, and into which said valve body is inserted,
an alignment groove which is formed on the inner wall of the insert hole from the side of the hole opening of said insert hole along the direction of inserting said valve body,
said valve body possessing a projection, which is placed on the circumference surface of the valve body, which is engaged with said alignment groove, and which can slide along said alignment groove, and
a cover which is screwed from said hole opening onto said insert hole, and which pushes and supports said valve body at the end thereof.
By having such a construction, there is no need for enlarging the diameter of the pipe, making it possible to moderate the restrictions of the thermostat placement. The engagement of the alignment groove with the projection makes it easy to carry out alignment, leading to the improvement in the workability of fitting the thermostat.